Let E(X) be the H-space of homotopy self-equivalences which are homotopic to the identity of a homogeneous Kähler manifold with maximal rank. The Lie algebra of derivations of a pure differential graded algebra with zero homotopy Euler characteristic allows us to use Sullivan's minimal model to study the rational homotopy theory of E(X). As an application we compute dim in the case when X is a certain flag manifold.